Washington DC is often cited as having some of the nation's worst traffic and congestion. In 2008, Forbes magazine found that Washington commuters spend 60 hours a year in traffic, which tied Atlanta, Georgia for having the worst traffic in the country after Los Angeles. However, the Washington area has the second-highest number of commuters in the country who walk, bike, carpool, or take public transportation.

The Washington Metropolitan Area Transit Authority (WMATA) operates the city's rapid transit system, Metrorail (most often referred to as simply 'the Metro'), as well as Metrobus. The subway and bus systems serve both DC and the immediate Maryland and Virginia suburbs. Metrorail opened on March 27, 1976 and presently consists of 86 stations and 106.3 miles (171.1 km) of track. With an average 950,000 trips each weekday in 2008, Metrorail is the nation's second-busiest rapid transit system in the country, after the New York City Subway.

Due to population growth in the Washington area, WMATA expects an average one million Metrorail riders daily by 2030. The need to increase capacity has pushed up plans to add 200 trains to the system, re-route subway cars to alleviate congestion at the busiest stations, and construct two additional Metro lines. The surrounding jurisdictions in the Washington area have local bus systems, such as Montgomery County's Ride On, which compliment service provided by WMATA. Metrorail, Metrobus and all local public bus systems accept SmarTrip, a reloadable transit pass.

Union Station is the second-busiest train station in the United States, after Penn Station in New York, and serves as the southern terminus of Amtrak's Northeast Corridor and Acela Express service. Maryland's MARC and Virginia's VRE commuter trains and the Metrorail Red Line also provide service into Union Station. Intercity bus service is available from the Greyhound Lines terminal in Northeast DC. Other private bus lines, such as the low-cost 'Chinatown' buses, mainly provide service between Washington and New York City.

Three major airports, one in Maryland and two in Virginia, serve Washington DC Ronald Reagan Washington National Airport, located just across the Potomac River from downtown DC in Arlington County, Virginia, is the only Washington-area airport that has its own Metrorail station. Given its proximity to the city, Reagan National has noise restrictions and extra security precautions as required by the Air Defense Identification Zone (ADIZ). Additionally, Reagan National does not have US Customs and Border Protection and therefore can only provide international service to airports that permit United States border preclearance, including: Nassau, Bahamas; Bermuda; Toronto; Ottawa; and Montréal.

Major international flights arrive and depart from Washington Dulles International Airport, located 26.3 miles (42.3 km) west of the city in Fairfax and Loudoun counties in Virginia. Dulles serves as the major east coast airline hub for United Airlines. Baltimore-Washington International Thurgood Marshall Airport, located 31.7 miles (51.0 km) northeast of the city in Anne Arundel County, Maryland serves as a hub for both Southwest and Airtran airlines.